In preparing a field for planting, disc tillers are commonly used to break up the soil of a plowed field and a ground-engaging implement such as a spike-tooth harrow is used to smooth and further reduce the soil cut by the disc blades. These two operations may be performed by separate passes over the field, the first with a tractor pulling a disc, the second with a tractor pulling a harrow. To avoid the need for making separate passes, harrows have been connected behind the disc tiller in a number of ways. Harrows have been mounted directly to the disc tillers, but because the weight of the harrow must be supported by the disc the weight and size of the harrow must be kept low to avoid uneven loads on the front and rear disc gangs of the disc tiller. Furthermore, some conventional discs are not sufficiently sturdy to carry the extra load of an attached harrow.
To take the load of the harrow off the disc, a separate trailer hitch with its own wheels and a single pivotable hitch point may be used for pulling the harrow behind the disc. However, to avoid interference with the harrow and the disc when executing turns, it is necessary to have a long pull bar on the harrow trailer which makes transport and manuevering of the combined implements cumbersome. When transporting the implements over roads or fields to be left uncultivated it is necessary to raise the discs and the harrow teeth above the ground.
What is needed is a hitch for mounting a harrow closely behind a disc cultivator which will not transmit significant loads to the disc itself yet which will permit easy manuevering of the implement assembly and transport of the harrow over roads.